• Composites Research
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• 제18권3호
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• pp.7-13
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• 2005

본 논문에서는 하이브리드 복합재 철도차량차체에 적용되는 복합적층판에 대한 저속충격시험을 수행하였다. 이를 위해 2.4J, 2.7J 및 4.2J의 세 가지 충격에너지 조건에서 세 가지의 다른 적층구조를 갖는 적층판에 대한 저속충격시험을 수행하였다. 시험에 적용된 직조된 카본/에폭시 적층판의 크기는 $100mm\times100mm$ 이다. 충격시험 후 충격하중이력, 흡수된 에너지 및 손상면적 등이 각 충격에너지와 적층순서에 따라 고찰되었다. 손상면적은 육안검사와 C-scan을 이용하여 동시에 검사하였다. 시험결과 흡수된 에너지는 $[fill]_8$, 적층판이 가장 높았고 $[fill_2,/warp_2)_s$ 적층판이 가장 낮았다. 또한 손상면적은 $[fill]_8$, 적층판에서 가장 넓은데 이것은 상대적으로 흡수에너지가 높기 때문이다.

• 한국해양공학회지
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• 제10권4호
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• pp.92-102
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• 1996

In this research, to develope the A1 7075/CFRP multilayered hybrid composites, CRALL(Carbon Reinforced aluminum lamiate) specimens were processed by autoclavecuring system that curing temperature, time, surface pretreatment condition of aluminum were constant. Andthe fatigye life and failure mechanism on CFRP volume fraction and fiber orientation of CRALLspecimens were investigated. A fatigue life was greatly influenced by effect of CFRP fiber volume fraction but it was less effected than those of fiber orientation. The fatigue failure arised from interface delamination of CFRP and aluminum sheet after shear fracture of aluminum layer. The failure mechanism is assumed that the aluminum laminates which divide the CFRP into many thim layers tend to arrest the failure propagation.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.121.1-121.1
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• 2005

• 수산해양기술연구
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• 제28권3호
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• pp.295-305
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• 1992

The critical strain energy release rate and the failure mechanisms of glass-carbon epoxy resin hybrid composites are investigated in the temperature range of the ambient temperature to 8$0^{\circ}C$. The direction of laminates and the volume fraction are [(+45, -45, 0, 0) sub(2) ] sub(s), 50%, respectively. The major failure mechanisms of these composites are studied using the scanning electron microscope for the fracture surface. Results are summarized as follows: 1) The critical strain energy release rate shows a maximum at ambient temperature and it tends to decrease as temperature goes up. 2) The critical strain energy release rate increases as the content of glass increases, and especially shows dramatic increase for the high glass fiber content specimens. 3) Major failure mechanisms can be classfied such as localized shear yielding, fiber-matrix debonding, matrix micro-cracking, and fiber pull-out and/or delamination.

• 한국해양공학회지
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• 제11권3호
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• pp.69-75
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• 1997

A A12024-T3 plate has been reinforced with AFRP to be a Hybrid-Composite, APAL. The fatigue life of the APAL has been investigated. The effects of bonding surface, numbers of AFRP bonded and AFRP orientation on fatigue life have been compared with A12024-T3 plate. Fatigue life of APAL has been remarkedly increased compared with that of A12024-T3 plate. The fatigue life has depended on bonding surface and AFRP orientation, but no relationship could be found with numbers of AFRP laminates.

• Structural Monitoring and Maintenance
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• 제7권3호
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• pp.233-259
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• 2020

Using bonded fiber-reinforced polymer laminates for strengthening wooden structural members has been shown to be an effective and economical method. In this research, properties of suitable composite materials (sika wrap), adhesives and two ways of strengthening beams exposed to bending moment are presented. Passive or slack reinforcement is one way of strengthening. The most effective way of such a strengthening was to place reinforcement laminates in the stretched part of the wooden beam (lower part in our case), in order to investigate the effectiveness of externally bonding FRP to their soffits. The model is based on equilibrium and deformations compatibility requirements in and all parts of the strengthened beam, i.e., the wooden beam, the sika wrap composite plate and the adhesive layer. The theoretical predictions are compared with other existing solutions. This research is helpful for the understanding on mechanical behaviour of the interface and design of the composite-wooden hybrid structures. The results showed that the use of the new strengthening system enhances the performance of the wooden beam when compared with the traditional strengthening system.

• 한국정밀공학회지
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• 제16권8호
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• pp.149-154
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• 1999

FRMLs(Fiber Reinforced Metal Laminates) is a new type of hybrid materials. FRMLs consists of high strength metal and fiber which are laminated using a structural adhesive bond(epoxy resin). The effect of resin mixture ratios on the fatigue crack propagation behavior and mechanical property of Aramid fiber reinforced aluminum composites was investigated. The epoxy, diglycidylether of bisphenol A(DGEBA) was cured with methylene dianiline(MDA) with or without accelerator(K-54). Eight kinds of resin mixture ratio were tested for the experiment ; five kinds of FRMLs(1))epoxy & curing agent) and three kinds of FRMLs(2)(epoxy & curing agent & accelerator). FRMLs(2) have a more effective characteristics on the fatigue crack propagation behavior and mechanical property than FRMLs(1)

• Composites Research
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• 제31권6호
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• pp.311-316
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• 2018

In the present study, the effect of GO in damping capacity of CF/epoxy laminates was studied via free vibration analysis. The composite laminates were manufactured by using vacuum assisted resin transfer molding technique. The damping properties of the prepared hybrid composites were determined in terms of natural frequency and damping ratio in free vibration test. The foremost aspire of this investigation was to compare the vibration properties i.e. natural frequency and modal damping of the prepared composites with the numerical results. The numerical study was carried out via FEA using $ANSYS^{TM}$ workbench software. The parametric study of the numerical models was also studied considering the beam free length and the beam thickness. It was found that the incorporation of GO enhanced the damping capacity of the composite and the variation of natural frequencies in mode1varied by 2-5% compared to the experimental study.

• Composites Research
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• 제17권1호
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• pp.18-28
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• 2004

섬유강화 적층 복합재 차체 구조물의 강도를 평가하기 위해 전체 적층판 접근방법의 적용을 제시하였다. 180km/h급의 한국형 틸팅열차의 하이브리드 복합재 자체 기본설계를 검증하기 위해서 구조해석을 수행하였으며 또한 복합재 적층판의 강도를 구하기 위해 기계적 물성시험을 수행하였다. 결과적으로, 한국형 틸팅열차의 복합재 자체 구조물에서 발생하는 응력값들은 모두 파손영역의 안전한 범위 내에 존재하였으며 전체 적층판 접근방법은 초기 기본석계 단계에서 하이브리드 복합재 자체 구조물의 파손을 예측하는데 매우 유용함을 증명하였다.

• 전기학회논문지
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• 제63권10호
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• pp.1412-1416
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• 2014

We report thin-film organic moisture barriers based on polystyrene(PS) laminates deposition by PECVD for an encapsulation of OLEDs. The organic polystyrene thin-film has the benzene ring structure and high hydrophobic characteristics and it was polymerized by PECVD in dry process. Life time properties of Ca test were obtained 32 minutes at the RF 100W process conditions. From the AFM test, the roughness of multi-layer thin-film was more excellent rather than that of a single-layer thin-film. In addition, 5 layers of the multi-layer film properties were obtained 45 minutes. So that the optical and electrical properties were not affected with these plasma polymerized organic thin-film encapsulation. For life time improvement, the inorganic $Al_2O_3$ thin-film were deposited 5nm using ALD atomic layer deposition. The WVTR(Water Vaper Transmission Rate) value of hybrid thin-film encapsulation in the optimum process conditions was resulted by less than $10-3g/m^2/day$. From the results of experiment, plasma polymerized hybrid encapsulation was suggested as the flexible display applications.